Significant shortening of leukocyte telomeres one year after childbirth in women with type 1 diabetes mellitus: a prospective cohort study

Background Telomere shortening is influenced by biological and environmental factors, which are especially pronounced during and after pregnancy in women with type 1 diabetes mellitus (T1DM). This study investigates the dynamics of maternal leukocyte telomere length (LTL) during pregnancy and the postpartum period in women with T1DM. Methods A prospective cohort of 74 pregnant women with T1DM was enrolled from February 2019 to January 2021 in Zagreb, Croatia. Leukocyte telomere length (LTL), measured as T/S ratio by quantitative PCR, was assessed at delivery (n=74) and one year postpartum (n=46). Result At delivery, median LTL was 2.64 (IQR: 1.87-4.59). One year postpartum, median LTL decreased significantly to 1.87 (IQR: 1.23-2.46), representing a 29% relative reduction (P < 0.001, Wilcoxon signed-rank test, r = 0.72). Neither HbA1c levels nor BMI significantly influenced LTL at delivery. No significant difference in LTL was observed between term and preterm deliveries. Conclusions Women with T1DM experience significant telomere shortening within the first year postpartum. While HbA1c and BMI showed no significant effects in this cohort, they remain potential modifiers of telomere dynamics and merit further investigation. These findings highlight the need for targeted postpartum care strategies in this high-risk population.